Prof. Cook has also done extensive work on the
STK toolkit, which contains both
libraries for physical modeling, and "ready-to-go" physical models, all
free of charge. STK is available from the Stanford Center for Computer
Research in Music and Acoustics (CCRMA).

If you're feeling intimidated by the subject of physical modeling, we have
a (very brief) tutorial
on the very subject.

There is also a list of Sound Lab publications that deal with physical modeling:

Lakatos, S., P. R. Cook, and G. Scavone. "Selective
Attention to the Parameters of a Physically Informed Sonic Model,"Acoustics Research Letters Online, Journal of the Acoustical Society of
America, May 2000.